Home made kayak trailer built by my neighbor and I. Modified harbor freight 40" x 48" kit. It will hold up to 5 boats or 4 boats and 4 bycicles (if you look close you can see the Yakima channels & spindels on the top level.
The link has other photos of this trailer including a close-up of the swivel support pad. I also have pictures of an aluminum mini kayak cart and my own trailer built from the same kit 3 years ago. Mine has a Stainless steel frame with a 40" x 80" cargo box. Also some pictures of the 14' x 20' boat storage shed we built this spring for $1,100. (See my "need some room..outside" post on Aug 2 for details on the building)